Graining process



Filed Jan. 17, 1928 Patented Oct. 25, 1932 UNITED STATES PATENT OFFICE LLOYD V. CASTO, OF DETROIT, MICHIGAN, ASSIGNOB TO OXFORD VARNISH CORPORA- TION, 0F DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN GRAIN ING PROCESS Application filed January 17, 1929. 'serial No. 333,048.

The object of this invention is to provide a process of reproducing high grade wood and other natural grain effects on metallic or other bases, which will more faithfully portray the tonal effects of the original wood pattern.

A more specific object is to provide a process for faithfully reproducing butt or burl walnut and the like, that is to say, woods which have more or less under-toning between the full tones, half tones, etc. of grain line coloring and the base or ground color.

The process is unique in that I use, in addition to the usual grain transfer as from an intaglio plate, an additional under-toning transfer, preferably from a second intaglio plate, prepared as will be hereinafter shown.

I propose to employ, as part of the process, a series of steps substantially in accordance with the patent to J. P. Henry, No. 1,548,465, particularly in obtaining the full grain lines in full tone, half tone, etc.

As disclosed in the Henry patent, the pattern to be reproduced, as on a metal panel, is first photographed in negative, then a positive plate or film is made photographically, and from this a carbon resist. The carbon resist is then used to form an etched printing plate; the darker portions of the pattern, the grain lines, being reproduced on the plate in the form of cavities of varying depth, making what is known as an intaglio plate. The cavities may be broken up into smaller cavities by the use of a screen in one of the photographic steps. covered with pigment of the desired color and theplate is then scraped clean, except for the cavities, and thereafter the design is transferred, preferably by means of a transfer roll, onto the panel to be grained.

By the use of an intaglio plate, produced as just described, and applying the design thereof over a suitable ground color, on say a metal panel, and suitably working the transferred design to blend the more faint grain coloring with the ground color, a comparatively faithful reproduction of origlnal woods may be effected: In the process, the full tones, half tones, etc. are brought out by reason of the fact that certain of the re- Afterward, the plate is.

cesses in the intaglio plate are shallower than others. However, the process is not adequate for reproducing such woods as butt or burl walnut, because these woods have faint under-tonings in a color between the grain color and ground color, which, notwithstanding careful blending, as by hand, cannot be brought out.

To obtain the under-tonings, I propose to use a second intaglio plate, which will be referred to as the under-toning plate. This under-toning plate may be produced, for example, by two methods, substantially similar, but each having variations to suit the subject to be reproduced. For example, the under-toning plate may be made, starting wlth an actual photograph of that portion of the subject which shows the undertonings, or it may be produced, starting with a hand traced pattern of that portion of the subject having the under-tonings.

In the case of the hand traced pattern, I preferably first lay a suitable transparent sheet of material, such as celluloid, over the original subject or pattern, and trace in a general pattern of the darker grain areas, particularly where the under-tonings appear to be showing past the darker grain lines. The tracing may be by means of an air brush, the color of any nature being thus sprayed onto the sheet of celluloid, making a rough equivalent of a positive photographic film of the pattern or parts thereof.

This celluloid sheet is now placed in contact with the usual carbon resist sheet and the sheet is exposed to light through the film. The carbon resist will thus be light treated, except where the design appears. The resist is also exposed to light through a suitable screen, such as the Rembrandt screen having opaque blocks separated by transparent thin lines. This results in breaking up the design into squares. The resist is then used to etch the plate either fiat or on a roll. Preferably, only a light etching is used, since the undertoning color is always faint, and it is therefore desirable to transfer only a small amount of color, corresponding to the under-toning, onto the panel or like base to be grained.

In selecting a color or pigment to be printed, using the under-toning plate, due regard is had to the ground color with which the panel is first coated, as in practically all of wood reproducing processes. The pigment transferred by the under-toning plate will naturally blend with the ground color, and the ground color will show throu h it, thus making a combination color of the ground and under-toning transfer, which should be a true representation of the under-toning color on the original pattern. In this process, a lighter ground color is used than ordinarily employed for graining with a single grain transfer. After the under-toning transfer has been applied to the ground color, as through the intermediacy of a gum transfer roll, other under-toning colors may be worked 1 by hand, using the original pattern as a master copy, and using the under-toning transfer as a guide to properly place the additional under-toning colors.

These colors vary with different wood samples, for example, butt and burl walnuts have faint under-tonings of green, red or gray. These colors may bestippled on and worked in. It is not essential that the special undertoning colors be applied at this point, since they may be applied after the second or main rain transfer is printed over the under-toning transfer. The first mentioned procedure in regard to the special under-toning colors is preferred, in order to obtain what is known as depth.

The process of obtaining an under-toning plate may be varied, in that, instead of making a tracing, as by hand, of the original design, I may first take a photograph, preferably by a brief exposure, and possibly blocking but those ortions of the origina design w erethe an er-tonin are not apparent to the eye. From this p otograph, a positive image late or film is made, then a carbon resist; a terwards, exposed through a screen, as taught by the Henry patent, and the resist is used to make the under-toning plate.

Various devices may be used in connection with producin the under-toning plate as just described, in order that an actual nonregistration will be had between the undertoning'transfer and the full grain transfer. However, it is to be understood thatit is not essential that there be any such non-registration, because the under-toning is clearly apparent when the two imprints are in true registration. Actual non-registration is obtained in any case where a synthetic design is used to make the printing element for the first transfer. This is, of course, assuming the nthetic design is produced in the commerclally tactical manner and not by an extremely skilled artist trying to copy each "and and every detail of the pattern.- When making the printing element through the usual photograhpic steps, and by etching, one of the photographic copies may he made out of focus to effect a blurred image, which will in turn automatically effect non-registration, irrespective of how one imprint is placed on the other.

Obviously, more than .one under-toning plate may be made and separately imprinted, but usually, due to the fact that there is only one predominating under-tone, this is not necessary. The under-tonings which do not predominate may, as previously stated, he worked in at practically any step in the process, though preferably after the under-toning design has been transferred onto the ground color.

In the accompanying drawing, I have shown in Fig. 1 an enlarged cross sectional view of the grained panel; Fig. 2 is an enlarged diagrammatic plan view of a portion of such grained panel, made by using a hand traced design of the full tones of the pattern as a first step in producing the under-toning plate and Fig. 3 is a similar plan view showing (again diagrammatically) the result of using an actual photograph as a first step in producing the under-toning plate.

In Fig. 1, l designates the panel body, 2 the coating of ground color, and 3 the pig- -ment applied by the first or under-toning transfer. It will be noted that this pigment appears as disconnected blocks, due to breaking up the design, as by the screen above mentioned. The first transfer may or may not be covered with a locking coat of lacquer or varnish, such as 4, this depending largely on whether or not such coating is warranted by the use which the panel will ultimately serve. The final transfer, appearing as heavier disconnected blocks 5, is now printed over the first transfer, and this is then covered with a coating of protecting lacquer or varnish 6; to be afterward rubbed down and polished to secure the desired finish. It will be noted that the disconnected blocks of pigment, both at 3 and 5, are of varying depth and cross sectional area. This is the natural result of etching the plate through a resist such as previously described. It will be further noted that the blocks at 5 are partially out of registration with the blocks 3, allowin the under-tone color at 3 to be seen alongsi e the full grain coloring 5, as well as through the more or less transparent colorin "at 5.

ig. 2 illustrates, in principle, the manner in which the under-tone transfer will appear when viewed through and alongside the darker and more closely spaced full tone grain lines. In Fig. 2, the under-tone transfer 3a spreads over the entire zone of closely spaced grain lines 5a as when the under-tone plate is made by first tracing the full tone design of the pattern on a transparent sheet of celluloid, as described. The zones of the grain line transfer where this overlies the under-tone transfer and is thereby given greater color intensity are indicated at 56. No special coloring, as by hand, is illustrated.

Fig. 3 illustrates, in principle, the manner in which under-tone patches 3a would appear with relation to the grain line patches 5a where both plates are made substantially in the same manner, i. e. starting with a photograph and where both transfers are printed in true registration. Here it will be seen that actual non-registration exists in certain zones, as would naturally result from separately working the transfers, as with a brush, to tone down the sharp outlines.

'It will be easily seen from the above, how the resulting panel will be a more faithful reproduction of the original, both in the matter of tone and depth, irrespective of the suggested variations in the process.

I claim:

1. The process of simulating natural grain pattern effects on a base having a hard surface, comprising, applying a ground color coating to such surface, preparing a plate or roll, by hand copying a general design from the original pattern corresponding in general to the darker design portions of such pattern, using the copy in the photographic chain of steps necessary to etch the plate or roll, preparing another plate or roll photographically and by etching, but using a photograph taken from the actual pattern design to be reproduced to distinctly copy the darker grain effects, and using said plate or rolls, one after the other, to effect successive imprints over the ground color.

2. The process of simulating natural grain pattern effects on a base having a hard surface, comprising applying a ground color coating to such surface, preparing a plate or roll by tracing portions of the design of the pattern to be copied, on a transparent sheet of material and using such sheet in place of photographic copy in preparing an etch resist, thereafter etching the plate or roll, then transferring the design from the plate or 1 roll, in pigment, to said hard surface, and

thereafter printing over the first transfer, the last imprint carrying the grain design in comparatively sharp contrast and in a color or shade darker than that of the first design transfer.

3. The process of simulating natural graining patterns of subjects having a ground color, a graining color and an intermediate undertone color, comprising producing undertones by applying a ground coating having a color considerably lighter than the natural ground color of the subject, makin a copy of the undertone outline of the subject and producing a printing plate correspond ing to such copy, transferring the pattern of such plate to the base over the said ground color while using a pigment which is partially transparent and having a color which substantially corresponds to the undertone coating and then printing the original graining design using a photographically designed engraved plate and a pigment the color of which corresponds substantially to the original graining color, said last transfer being applied over the area covered 'by the first transfer.

In testimony whereof, I hereunto aflix my signature.

LLOYD V. 'CASTO.

ISO 

